Use of photo-based 3D photogrammetry in analysing the results of laboratory pressure grouting tests

This paper presents a non-destructive, low-cost, photo-based, 3D reconstruction technique for characterizing geo-materials with irregular shapes of a relatively large size. After being validated against two traditional volume measurement methods, namely the vernier caliper method and the fluid displacement method for regular and irregular shapes, respectively, 3D photogrammetry was used to analyse the grout bulbs formed in laboratory pressure grouting tests. The reconstructed 3D mesh model of the sample provides accurate and detailed 3D vertex data, which allowed the volume, densification efficiency and bleeding behaviour of the grout bulbs to be analysed. Comparing the bulb section views at different grouting pressures also offers an intuitive observation of the grout development and propagation process. Moreover, the 3D vertex data and surface area included in the model are of great importance in validating numerical predictions of the pressure grouting process and analysing the interface shear resistance of grouted soil nails or anchors. Compared to existing approaches, the new 3D photogrammetry method possesses several key advantages: (a) it does not require expensive, specialized equipment; (b) samples are not destroyed or modified during testing; (c) it allows to reconstruct objects of various scales and (d) the software is public domain. Therefore, the adoption of this 3D photogrammetry method will facilitate research in the pressure grouting process and can be extended to other problems in geotechnical engineering.     

太原西山中奥陶统脱白云石化定量研究

<正> 碳酸盐岩的脱白云石化作用,不仅是岩溶研究的一个重要方面,而且还是岩溶含水层系演变的一种主要地球化学作用。近二十年来,巴克和汉肖通过对佛罗里达和尤卡坦的第三纪碳酸盐岩含水层做了大量的理论研究,他们认为“在一个壮年含水层系中,控制其渗透分布的一个主要作用是白云石随石膏溶解而溶解,同时发生方解石的沉淀(脱白云石化作用)”      

韧性剪切过程中金沉淀富集的新机制

一般认为,金的沉淀是因为成矿热液在宏观上已达到金络合物失稳、分解的条件。笔者认为金在黄铁矿、毒砂等硫化物矿物中富集的原因,是这些矿物生长时造成了在其生长面附近的微区内会出现Ｅｈ值及（或）Ｓ＾２－、［ＡｓＳ］＾３－等浓度的局部降低,以致引起了金络合物在此微区内的失稳、分解,分解出来的金将就近附着在矿物的生长面上及随后被包围。成矿热液此时在宏观上不一定已达到金络合物的分解条件。韧性剪切过程中石英普遍会     

青藏高原三维变形运动学的时段划分和新构造分区

青藏高原形成至今经历了4个互有叠接的构造期。α期以南北缩短和向北推移为主,主要发生在45～35 Ma期间,β期表现为长周期缓慢隆升,在35～5.3 Ma期间占主导地位;γ期为短周期快速隆升阶段,自5.3Ma开始,3.0 Ma以后逐渐达到高峰;δ期以东西向伸展变形为特征,3.0 Ma以前出现在喜马拉雅地区,3.0 Ma以后遍及整个高原.第四纪以后表现为占主导地位的变形运动形式。根据γ期和δ期构造变动在空间和时间上的不均匀性,把青藏高原划分为西藏、羌塘和柴达木3个构造域。     

从微体化石看西太平洋暖池的形成与演化

通过对南海大洋钻探ODP第184航次的ODP1143站和ODP1146站以及中德合作"太阳号"95航次的南沙海区17957-2柱状样中微体化石进行定量分析,提取了近18MaB.P.以来南海上部海水垂向结构的变化.结果发现11.5～10.6MaB.P.之间和3.6～3.3MaB.P.以来南海温跃层深度的南北梯度明显增大,指示了西太平洋暖池雏形的开始和现代暖池的最终形成,且分别对应于印度尼西亚海道和巴拿马地峡的关闭.此后,南沙海区的温跃层深度自约0.9MaB.P.逐渐变浅,至约0.15MaB.P.又再变深,反映了西太平洋暖池的减弱和再次加强.因而,晚新生代西太平洋暖池的形成和演化呈现阶段性.     

地幔平衡部分熔融和岩浆分离结晶成因岩浆岩的判别

本文在讨论Ⅰ型（地幔平衡部分熔融成因）和Ⅱ型（岩浆分离结晶成因）岩浆岩元素丰度关系公式的基础上，建立了Ⅰ型和Ⅱ型岩浆岩系成因判别公式及判别法则。     

Age and metal source of orogenic gold deposits in Southeast Guizhou Province,China: Constraints from Re-Os and He-Ar isotopic evidence

The orogenic gold deposits in Southeast Guizhou are an important component of the Xuefeng polymetallic ore belt and have significant exploration potential, but geochronology research on these gold deposits is scarce. Therefore, the ore genetic models are poorly constrained and remain unclear. In the present study, two important deposits(Pingqiu and Jinjing) are investigated, including combined Re-Os dating and the He-Ar isotope study of auriferous arsenopyrites. It is found that the arsenopyrites from the Pingqiu gold deposit yielded an isochron age of 400 ± 24 Ma,with an initial ~(187)Os/~(188)Os ratio of 1.24 ± 0.57(MSWD = 0.96). An identical isochron age of 400 ± 11 Ma with an initial ~(187)Os/~(188)Os ratio of 1.55 ± 0.14(MSWD = 0.34) was obtained from the Jinjing deposit. These ages correspond to the regional Caledonian orogeny and are interpreted to represent the age of the main stage ore. Both initial ~(187)Os ratios suggest that the Os was derived from crustal rocks. Combined with previous rare earth element(REE), trace elements, Nd-Sr-S-Pb isotope studies on scheelite, inclusion fluids with other residues of gangue quartz, and sulfides from other gold deposits in the region, it is suggested that the ore metals from Pingqiu and Jinjing were sourced from the Xiajiang Group. The He and Ar isotopes of arsenopyrites are characterized by ~3 He/~4 He ratios ranging from 5.3 × 10~(-4) Ra to 2.5 × 10~(-2) Ra(Ra = 1.4 × 10~(-6), the ~3 He/~4 He ratio of air), 40 Ar=/~4 He ratios from 0.64 × 10~(-2) to 15.39×10~(-2), and ~(40)Ar/~(36)Ar ratios from 633.2 to 6582.0. Those noble gas isotopic compositions of fluid inclusions also support a crustal source origin,evidenced by the Os isotope. Meanwhile, recent noble gas studies suggest that the amount of in situ radiogenic ~4 He generated should not be ignored, even when Th and U are present at levels of only a few ppm in host minerals.     

近400年来新疆策勒红柳沙包稳定氧同位素与气候变化

建立红柳沙包沉积纹层年代序列和提取气候环境信息是高分辨率古气候环境变化研究的重要手段。利用策勒达玛沟红柳沙包高度约450 cm沉积纹层红柳落叶的稳定氧同位素数据,结合策勒气象站1960~2011年观测数据,运用移动平均法对稳定氧同位素和气象数据进行平滑处理后,运用相关分析及逐步回归法,定量重建了策勒地区近400年来的4月平均气温和3月降水量序列。研究结果表明:红柳落叶δ^18O平均值为33.96‰,波动范围为27.18‰~44.07‰,波动幅度为16.89‰,δ^18O变化受多个气候要素的综合影响。δ^18O与4月平均气温呈显著负相关,与2月和12月平均气温呈显著正相关;δ^18O与10月、4月、5月、9月、7月以及全年的空气相对湿度呈显著正相关;δ^18O与3月、9月和8月的降水量呈显著正相关,与2月降水量呈显著负相关;δ^18O与2月日照时数呈显著正相关,与9月和10月的日照时数呈显著负相关。策勒地区近400年来气候变化可划分4个阶段:1635~1725年为暖干期,1726~1792年为冷湿期,1793~1897年为暖干期,1898~2009年为冷湿期。     

Numerical Simulation of Transportation of Marine Microplastics A Review

The temporal and spatial discontinuity of microplastic sampling data restricts the investigation on their source, sink, transport pathway and trend. Numerical simulation combined with sampling investigation can comprehensively study the effects of microplastic characteristics, meteorology and hydrodynamics on the distribution and transportation of microplastics. In this paper, the studies of microplastic numerical simulation were reviewed from the aspects of numerical simulating research and their applications in microplastic tranportation, and the results were summarized as follows: The construction of the main driving force (current); the influence of environmental factors, such as wind, waves, topography and extreme sea conditions on the properties of microplastics with different characteristics (particle size, density, shape) and their tranportation; the application of numerical simulation in the study of microplastic removal. Based on progress on the study of numerical simulation of marine microplastics, the future directions were pointed out that the further simulating studies should focuson the spatio-temporal distribution and evolvement of microplastics by combining sampling data and numerical model, the simulating research on the relationship between microplastic parameters (roughness, wind drag coefficient, settling rate, resuspension rate and biofouling rate) and (meteorological and ocean) dynamic condition. Moreover, the results of simulating sensitivity experiments should be compared with sampling and laboratory testing data to improve the empirical parameters and formulas of numerical model.     

蚌埠隆起区石榴辉石岩变质P-T轨迹的构建

蚌埠隆起区位于华北克拉通东南缘,胶—辽—吉造山带的最南端,主体由五河杂岩组成。前人对该地区的研究主要集中于同位素年代学和变质温压条件研究,其中变质P-T条件研究结果差异较大,以压力变化最为显著,对峰期变质P-T条件缺乏统一认识。本文对蚌埠隆起区石榴辉石岩进行了大量的岩相学、矿物化学成分分析,表明该岩石记录了3期变质作用,其中S-M1和S-M2的矿物组合类似为Grt+Cpx+Opx+Amp+Pl+Ilm,S-M3的矿物组合为Cpx+Amp+Pl+Grt （极边窄带）。结合变质温压条件分析和锆石U-Pb年代学分析,本次主要取得以下几点认识：1）石榴辉石岩WS047-1中记录的3期变质作用,温压条件分别为T-M1 = 616 ℃～647 ℃、P-M1 = 1.03～1.08 GPa,T-M2 = 721 ℃～837 ℃、P-M2 = 1.11～1.29 GPa和T-M3 = 531 ℃～607 ℃、P-M3 = 0.81～0.91 GPa,经历了由较高压力的角闪岩相→中-低麻粒岩相→角闪岩相的变质过程;2）据变质温压条件分析知,蚌埠隆起区具有顺时针的P-T轨迹特征,S-M1→S-M2和S-M2→S-M3分别为近等压升温和近等压降温的缓慢过程;3）石榴辉石岩锆石U-Pb年代学结果主要分为4组：1 839±13 Ma、1 925±31 Ma、2 041±55 Ma和2 762±14 Ma,其中峰值变质年代为1.93～1.84 Ga;4）结合温压条件和锆石U-Pb年代学分析结果,本文认为蚌埠隆起区的P-T轨迹与弗朗西斯科型俯冲或大陆碰撞环境的P-T轨迹较为类似,其应与1.93～1.84 Ga华北克拉通东、西陆块的碰撞拼合及胶—辽—吉造山带形成时限基本吻合。本次研究为深入理解华北克拉通的构造演化特征和蚌埠隆起区的变质作用及演化,提供了大量可靠的科学资料。